While I agree with your sentiment in principle, I fear that
things are not so simple. I know from your other posts that you
already agree with me on this but I'll elaborate for the sake of
discussion.
Each individual does not live in isolation, but as part of a larger
group and universe that we interact with. This necessitates that we
have some shared beliefs. And of course, the fundamental standard
of any shared believe would be the truth.
Atheists/materialists/naturalists believe that the way to discover
the truth is through science and reason. Religious people believe
that the truth can be revealed through supernatural means.
In most cases, we don't really care what other people believe
unless it affects us. Unfortunately, most beliefs affect how one
behaves, in which turn affects others.
For example, I may believe I am God and you were born to serve me.
You wouldn't care if I believed that unless I actually expected you
to serve me. In which case you would probably show me the middle
finger and ask me to F off.
The advantage of using science and evidence as the standard of
determining truth is that everyone can agree on it. Obviously,
science is not always right - we sometimes misinterpret evidence -
but it's the best we can do. We all see and observe the same
things. For religious interpretation, anything goes.
You said that some just believe there's a cosmic purpose in their
existence. If religious people left it at that, I wouldn't have a
problem. However, religious people believe in things like the Great
Commission that makes it a religious obligation for them to force
their beliefs on others. Let's not even get into Islam.
Religion is also so fundamental to belief systems that many times,
people don't even realize that their belief is religious in nature.
For example, the issue of pornography and prostitution. Why is
pornography illegal? Why is prostitution frowned upon. Personally,
I think if a guy wants sex, it is more moral for him to go to a
prostitute than to lie to a girl to get sex. What is the basis for
monogamy too? Why is sex outside of marriage frowned upon. We could
go on to many other issues. Abortion. Euthanasia. Stem-cell
research. Drugs. Blasphemy. Apostasy. The list goes on.
I've said this many times but I totally disagree with the
characterization that I try to convert people to atheism. Atheism
is not a belief system. What I advocate is people should belief
things for a reason and that reason should be science and evidence
as that is the ONLY basis of common understanding.